1. Field of the Invention
The present invention relates to a system for driving and controlling a shield such as a window or door for the open area of a window or doorway.
2. Description of the Prior Art
For example, the side and roof windows of an automobile are equipped at their open areas with shielding panels for adjusting the degrees of opening thereof. The passenger positions the panels to suitably set the degrees of opening of the panels. In pursuit of the operability, there has been mounted on the automobile a system which is equipped with an electric drive mechanism for driving those panels.
In the system of this kind, a corresponding motor of the electric drive mechanism is energized by a switching operation so that the system can be remotely controlled. If the operating switch is arranged around the driver's seat, for example, there can be attained a merit that the driver can freely adjust the degree of opening of a remote window (e.g., a side or roof window, as will be hereinafter referred to) while he is driving the car.
However, this merit of remote control leads to a demerit that the confirmation of the state of the window may be omitted. In order to eliminate this demerit, therefore, there have been invented a variety of systems for interrupting the drive of the panel or opening the panel if any catch between the window frame and the panel is detected while the panel is being closed.
In Japanese Patent Publications Nos. 47 - 11126 and - 44445, for example, there is disclosed a safety system for a power window, in which a tape-shaped switch is arranged in the frame of the window so that the motor for the electric drive mechanism may be deenergized if the switch is turned on.
In Japanese Patent Application No. 61 - 226679, moreover, there is disclosed a safety system for a closing member control device for detecting that catch by means of a piezoelectric wire.
In Japanese Patent Applications Nos. 61 - 69389 and - 39390, still moreover, there is disclosed a DC motor control method of monitoring the energized state of the motor of an electric drive mechanism in terms of a motor energizing current.
According to these disclosures, the aforementioned demerit of the remote control is eliminated because the drive of the panel is interrupted or the panel itself is opened if the catch between the window frame and the panel is detected while the panel is being closed.
In any of the techniques disclosed in the examples enumerated above, however, the motor of the electric drive mechanism is controlled if the catch, if any, between the window frame and the panel is detected. This operation means that it is impossible to avoid an uncomfortable experience of having a finger or the like caught no matter how it might be short or light if the finger is erroneously placed between the window frame and the panel.